The comment that left William 'fuming' while playing drinking game with Kate

Most of us have had embarrassing moments involving alcohol and, if new reports are to be believed, so have the Duke and Duchess of Cambridge.

It's claimed William and Kate played the drinking game 'Never Have I Ever' while attending the University of St Andrews – and things got a little awkward.

According to royal author Katie Nicholl one of Prince William's ex-girlfriends was in the room and taking part in the game.

The rules state players gather in a circle and one says a statement about he or she has never done before, claiming 'never have I ever'. Anyone who has done the action the first player says must drink.

In her 2011 book, The Making of a Royal Romance, Nicholl claims William's ex Carly Massy-Birch made a comment that left him fuming.

Quoting a source Nicholl writes: "When it was Carly's turn to play she announced, 'I've never dated two people in this room,' knowing full well that William was the only one who had because Kate was sitting next to him".

According to the source, Wills "shot a thunderous look" at Carly after she made the comment. He then said, under his breath, "I can't believe you just said that".

The book claims Kate was not impressed and has not spoken to Carly since the incident.

Prince William and Kate famously met and fell in love while attending university together. But before Kate came along, and changed his life forever, William briefly dated Carly during his first semester.